Tomb Stalkers are massive and scary looking constructs used by the Necrons. Seriously these things are bigger than your divisions of METHUL BAWKSES and are roughly the size of a Imperium Super-Heavy Tank and even a Knight. And did I mention they look like giant centipedes of doom?
Tomb Stalkers were previously an unseen form of construct used by the Necrons and are noted for being swift, tireless and relentless engines of destruction that have the single-minded task of protecting the ancient sepulchres of Necron Lords. As such, their function is pretty similar to the Canoptek Spyder, except while the Spyders usually repair broken Necron Warriors, the Tomb Stalker is going to wreck your armored columns.
The arcane machinery within a Tomb Stalker allows it to detect the pulse of life through hundreds of meters of solid rock allowing it to track its prey with ease. This, combined with a type of phase field, allow it to tunnel through solid matter as if they were a Necron Trygon. Ripping apart infantry and tanks until all is dust.
Tomb Stalkers are typically armed with a devastating mixture of Gauss weaponry as well as razor-edged talons, giving a Necron army a powerful mixture of firepower and combat agility. For added anti-tank bonuses (As if they aren't already raping your tanks in the battlefield), a Tomb Stalker can be upgraded into a Tomb Sentinel.